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DS1857

Dual Temperature-Controlled Resistors with

External Temperature Input and Monitors

______________________________________________ Maxim Integrated Products 1

For pricing delivery, and ordering information please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

General Description

The DS1857 dual temperature-controlled nonvolatile

(NV) variable resistors with external temperature input

and monitors consists of two 50kΩ 256-position linear

variable resistors, two analog monitor inputs (MON1,

MON2), and an external temperature sensor input. The

device provides an ideal method for setting and tem-

perature-compensating bias voltages and currents in

control applications using minimal circuitry. The vari-

able resistor settings are stored in EEPROM memory

and can be accessed over the 2-wire serial bus.

Applications

Optical Transceivers

Optical Transponders

Instrumentation and Industrial Controls

RF Power Amps

Diagnostic Monitoring

Features

♦ Four Total Monitored Channels (Temperature,

V

CC

, MON1, MON2)

♦ Two External Analog Inputs (MON1, MON2)

♦ Interface to External Temperature Sensor (LM50)

♦ Two 50kΩ, Linear, 256-Position, Nonvolatile

Temperature-Controlled Variable Resistors

♦ Resistor Settings Changeable Every 2°C

♦ Access to Monitoring and ID Information

Configurable with Separate Device Addresses

♦ Resistor Disable (Open-Circuit) Function

♦ 2-Wire Serial Interface

♦ Three Address Lines for Multiple Devices

♦ Operates from a 3.3V or 5V Supply

♦ SFF-8472 Compatible

Ordering Information

Rev 0; 1/03

PART

TEMP RANGE

PIN-PACKAGE

DS1857E-050

-40°C to +95°C

16 TSSOP

DS1857E-050/T&R

-40°C to +95°C

16 TSSOP

(Tape-and-Reel)

DS1857B-050

-40°C to +95°C

16 Ball CSBGA

A

TOP VIEW

B

C

D

1

16-BALL CSBGA (4mm x 4mm)

1.0mm PITCH

16 TSSOP

324

EXTTMP

A0WPENRHIZ

MON2MON1L0GND

H1V

CC

SCLA1

L1H0SDAA2

DS1857

SDA

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

SCL

A0

A1

A2

WPEN

RHIZ

GND

V

CC

H1

L1

H0

L0

EXTTMP

MON2

MON1

Pin Configurations

DS1857

SDA

1

2

3

4

5

6

7

8

16

0.1µF

15

14

13

12

11

10

9

SCL

A0**

A1**

A2**

WPEN

RHIZ

GND

V

CC

H1

L1

H0

L0

EXTTMP

MON2

MON1

Tx DISABLE

TO EXTERNAL TEMPERATURE

SENSOR, SUCH AS LM50

DIAGNOSTIC

INPUTS

0 TO 2.5V FS

TO LASER BIAS

CONTROL

TO LASER MODULATION

CONTROL

DECOUPLING

CAP

Rx POWER*

Tx BIAS*

*Rx POWER AND Tx BIAS CAN BE ARBITRARILY

ASSIGNED TO THE MON INPUTS.

**ADDRESS INPUTS DETERMINE THE MAIN DEVICE 2-WIRE

SLAVE ADDRESS WHEN ADFIX = 0. THIS ADDRESS MUST BE

DIFFERENT THAN THE AUX DEVICE ADDRESS WHEN ADEN = 0.

V

CC

V

CC

V

CC

= 3.3V

4.7kΩ4.7kΩ

2-WIRE

INTERFACE

GROUND TO

DISABLE WRITE

PROTECT

Typical Operating Circuit

1 2 3 4 5 6 ... 21 22

Résumé du contenu

Page 1

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors______________________________________________ Maxim Integrated

Page 2 - DC ELECTRICAL CHARACTERISTICS

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors10 ____________________________________________________________

Page 3 - ANALOG VOLTAGE MONITORING

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors_______________________________________________________________

Page 4 - AC ELECTRICAL CHARACTERISTICS

DS1857Register MapA description of the registers is below. The registersare read only (R) or read/write (R/W). The R/W registersare writable only if w

Page 5 - ACTIVE SUPPLY CURRENT

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors_______________________________________________________________

Page 6 - = 5.0V, T

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors14 ____________________________________________________________

Page 7 - Pin Descriptions

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors_______________________________________________________________

Page 8

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors16 ____________________________________________________________

Page 9 - Monitored Signals

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors_______________________________________________________________

Page 10 - Table 5. ADEN and ADFIX Bits

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors18 ____________________________________________________________

Page 11 - Table 7. Auxiliary Device

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors_______________________________________________________________

Page 12 - Main Device

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors2 _____________________________________________________________

Page 13 - Main Device (continued)

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors20 ____________________________________________________________

Page 14

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors_______________________________________________________________

Page 15

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and MonitorsMaxim cannot assume responsibility for use of any circuitry oth

Page 16 - Table 01h

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors_______________________________________________________________

Page 17 - Table 02h

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors4 _____________________________________________________________

Page 18 - 2-Wire Operation

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors_______________________________________________________________

Page 19 - Read Operations

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors6 _____________________________________________________________

Page 20 - 2-Wire Serial Port Operation

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors_______________________________________________________________

Page 21 - Chip Topology

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors8 _____________________________________________________________

Page 22

DS1857Dual Temperature-Controlled Resistors withExternal Temperature Input and Monitors_______________________________________________________________

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